Download Metamorphic Rocks and Mountain Building Section A

Surface Processes
NAME:_________________________________
Environmental Geology 103 Lab
Part 1: Metamorphic Rocks and Mountain Building
Section A: Rock Cycle Review
Click on the following link and answer the questions below:
http://www.classzone.com/books/earth_science/terc/content/investigations/es0602/es0602page02.cfm?chapter_no=i
nvestigation
1. Click on the play button until the animation stops and shows lava flowing out of a volcano. What type of rock is
being formed here? _____________________________________
2. Click Continue and when the animation stops again you will see a blinking rain cloud. What process is producing
sediment? ______________________________________
3. Click Continue and when the animation stops again you will see sediment being transported. How is the
sediment moving? __________________________________
4. Click continue to see the transported sediment deposited on the seafloor. Click on the blinking wedge of
sediment and a pop-up window will show a short movie of sediment deposition. Answer the following:
a. What happens to the streamflow as it enters deep water?
b. Gravel sized sediments accumulate near shore. Is the velocity of the water here relatively fast moving,
slow moving, or calm (circle one)?
i. If these sediments compact into a sedimentary rock, name the rock you think would be
formed:___________________________________
c. Sand grains settle out after the gravel, when the stream can no longer carry them. Is the velocity of the
water here relatively fast moving, slow moving, or calm (circle one)?
i. If these sediments compact into a sedimentary rock, name the rock you think would be
formed:___________________________________
d. Clay sized particles settle out farther from shore. Is the velocity of the water here relatively fast moving,
slow moving, or calm (circle one)?
i. If these sediments compact into a sedimentary rock, name the rock you think would be
formed:___________________________________
5. Close the pop-up window and click on Continue in the Rock Cycle Animation to see the process of compaction
and cementation, which form sediments into sedimentary rocks.
6. Click continue to see the beginning of Metamorphism. Then click on the blinking rocks that are dragged
downward, via subduction, to see a pop-up window. Play the animation on the pop-up window and answer the
following:
a. What type of rock (of the three rock types) is shown prior to metamorphism?
b. What two processes cause metamorphism?
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c. As pressure squeezes minerals what happens?
d. Aligned mineral grains form in the now metamorphosed rock. What is this called?
e. The original rock at the beginning of this short movie was Diorite. What is the new metamorphosed
rock?
7. Close the pop-up window and click Continue in the Rock Cycle Animation to see the completion of
metamorphism.
Section B: Metamorphic Rocks and Mountain Building
8. Refer to the rock cycle diagram on p.88 in your manual. Which rock types can be metamorphosed?
Page 176 will help you will the following questions:
9. Recall from your prelab the term “preferred orientation.” There are two types of preferred orientation, foliation
and lineation. We will simplify them by referring to both as foliation. What is foliation?
10. Refer to Figure 7.3b on p.170 of your manual. What is directed pressure, or differential stress? (Show with
arrows)
11. Complete the Play-Doh experiment and then answer questions 7 and 8. DIRECTIONS:
a) Take bit of Play-Doh, shape it into a ball, and insert a few pennies at various depth and orientations (see
below, left).
b) Draw lines to represent your pennies in the circle below, left.
c) With your hands apply pressure to opposite sides of the ball. Your ball should become elongated, like
the drawing below, right.
d) On the drawing below on the right, draw arrows representing the direction with which you applied
stress (pressure) to the ball.
e) Also on the drawing on the right, draw lines representing how your pennies look after pressure was
applied.
Before pressure
is applied
After pressure
is applied
12. After you applied pressure did the pennies orient parallel or perpendicular to the direction of pressure applied
(circle one)?
13. What texture is represented by the pennies?
14. Which of the following has the same relative direction as your arrows in the above, right drawing? (Circle one)
a. Two plates pulling apart
b. Two plates coming together
c. Two plates sliding past each other
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15. Therefore, foliated metamorphic rocks are commonly formed at
________________________________________ plate boundaries.
16. In your prelab, you identified two main types of metamorphism, what are they (see p.172)?
17. Which type of metamorphism is associated with convergent plate boundaries?
18. Describe that type of metamorphism:
Section C: Metamorphic Rock Identification
Take rocks 29, 30, 31, 34, and 36 to your table.
19. Of the 5 rocks, three of them are foliated. Remembering that foliation results in a layering of minerals, put them
in a pile and list the specimen numbers:
20. The remaining two rocks are non-foliated. Put them in a pile separate from the foliated rocks and list the
specimen numbers:
21. Refer to pg.181 in your manual for the following questions.
a. What is metamorphic grade?
b. What happens to foliation with increasing metamorphic grade?
22. Observe the three foliated rocks and put them in order of increasing metamorphic grade based on your answers
above:
Least metamorphosed _______ _______ ______ Most metamorphosed
WORD BANK for metamorphic rocks:
Quartzite * Gneiss * Slate * Schist * Marble
23. Using table 7.2 on p.179, and the word back above, identify the three foliated rocks:
a. #29:_______________________________
b. #34:_______________________________
c. #36:_______________________________
24. Now that you know which rocks are foliated, and their metamorphic grade, put them in the correct blank in the
Metamorphic Rock table, and write the rock name and specimen # in the corresponding blank.
25. The minerals present in a metamorphic rock, or its composition, can also be used for identification. The two
non-foliated rocks you have can be distinguished by their composition. Use Table 7.2 on p.179 to answer the
following:
a. Rock # 30 reacts with HCl, as does the mineral calcite. Which of your two rocks contains the mineral
calcite? ____________________________________
b. Rock # 31 contains the mineral quartz. Which of your two non-foliated rocks contains the mineral
quartz? _______________________________
26. Using the composition of the non-foliated metamorphic rocks, put the two rocks you identified above in the
correct square in the metamorphic rock table, and write the rock name and specimen # in the corresponding
blank.
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27. The parent rock, or protolith, is the rock that undergoes metamorphism. Pull rock specimen #s 13, 19, and 20.
These are sedimentary rocks that are common protoliths. Put them in the appropriate row in the Metamorphic
Rocks table. Answer the following:
a. Which protolith (name the rock) metamorphoses to foliated metamorphic rocks?
b. Why do you think this is?
c. Which two protoliths metamorphose to non-foliated metamorphic rocks?
d. Why do you think this is?
Part 2: Landslides
Note: There are several different types of landslides, as discussed in the back of your manual in Chapter 16. We are going
to use the general term landslides to refer to slope failure with a fast velocity.
1. Once mountain building begins, so does erosion. There are several agents of erosion, including landslides. Using
the glossary in the back of your manual, define erosion:
2. Click on the following link and observe the landslide risk map. The pink and red areas have the highest risk and
incidence of landslides, followed by the green; areas represented by the light beige have the lowest risk
http://landslides.usgs.gov/hazards/nationalmap/
a. Where do you see high landslide risk?
b. What do these areas have in common?
3. Click on the following link about causes of landslides, and next to each cause below write if the cause is natural
or anthropogenic (from humans): http://www.ga.gov.au/scientific-topics/hazards/landslide/basics/causes
a. Removal of vegetation: ____________________________
b. Earthquakes: ____________________________
c. Modification of the slope (Ex. Road-cuts): ____________________________
d. Intense rainfall: ____________________________
e. Slope angle: ____________________________
f. Geology (sediment or rock on the slope): ____________________________
4. How do you think removal of vegetation can contribute to increased landslide risk (see p.606 in the BACK of your
manual for help)?
5. Examine rock specimen #s 3, 13, 23, and 29 closely and think about the characteristics that might make a
mountain made of that rock more or less susceptible to landslides. Fill out the two blank columns in the table
below:
More or less
Rock Name and #
Rock Type
What characteristics make this rock more or
susceptible
less susceptible to landslides?
to landslides?
Granite #3
Sandstone #13
Conglomerate #23
Slate #29
(uncompacted, crystalline, layered, foliated?)
Igneous
Sedimentary
Sedimentary
Metamorphic
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6. Read the following article about the devastating Oso, WA landslide of 2014, and answer the following questions:
http://news.nationalgeographic.com/news/2014/07/140722-oso-washington-mudslide-science-logging/
a. How many people died as a result of this landslide?
b. What two factors are mentioned that scientists think contributed to the landslide?
c. At the time of the slide, scientists were surprised at the extent of the landslide. However, recent LIDAR
images of the area revealed what?
Part 3: Rivers (Streams)
As you saw in the rock cycle animation in the beginning of this lab, rivers are another major agent of mountain and
landscape erosion. Your book refers to this topic as streams and we will use the terms interchangeably.
Section A: Gradient-What determines how fast a river flows?
Use p.238 in your manual to help you answer the following questions.
1. What does the gradient of a river tell you?
2. What does the sinuosity of a river measure?
3. What is the equation for sinuosity?
4. Let’s compare the sinuosity and gradient of two different rivers on a topographic map. Fill out the table below
(which is Ex.103a in your manual) using Fig.10.4 on p.240:
Bighorn River (A-B)
Unnamed Tributary (C-D)
Channel Length (miles)
Straight-line length (miles)
Sinuosity (NO units!)
Highest elevation (feet)
3870’
Lowest elevation (feet)
3850’
Vertical drop
(Highest elevation-Lowest elevation)
GRADIENT
(Vertical drop/channel length)
5. Which river has the steeper gradient?
6. Does that river have a straighter or a more meandering channel?
7. What can you conclude about the relationship between sinuosity and gradient?
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8. See p.245 and Fig.10.7 on p.244.
a. Which of the two valley types is wider, with a narrower channel width?
b. How does this wider valley form?
c. When more water enters a broad, flat valley, what happens?
d. When more water enters a V-shaped valley, what happens?
e. Which valley type has the most vertical erosion?
Section B: Features of a floodplain
As a river meanders it carves a landscape in the floodplain with distinguishable features, which can tell us where the
river has been in the past. Let’s explore these floodplain features. Pages 245-246 in your manual will help you answer
the following questions:
9. What is a floodplain?
10. Turn to p.238 in your manual and look at the three rivers in Fig.10.3.
a. Which has the biggest floodplain?
b. Which river has almost no floodplain?
c. What is the relationship between sinuosity and width of the floodplain?
11. Watch this animation to see how a river meanders and carves a landscape, and use pgs.244-45 to help answer
the questions below: https://www.youtube.com/watch?v=8uV-BuBpIFw
a. Does sediment accumulate (accrete) on the inside or outside of a meander?
b. Does sediment erode on the inside or outside of a meander?
c. What is the name of the feature created when a meander becomes so pronounced that it is cut off from
the channel?
d. If that feature is not filled with water, what is it called?
e. If you were looking at a topographic map and saw an oxbow lake, or a meander scar, what would that
tell you about that area?
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12. In the drawing of a river meander below, label the following (if the feature appears more than once on the river,
just pick one to label)
a. *Point bar * Cut Bank * Channel * Floodplain * Oxbow Lake *
b. On one of the meanders, label areas of erosion with an X and areas of accretion with a +
Use the topographic maps on pages 247-48 to answer the following questions (Fig.s 10.9 a, b: NOTE that these are two
separate maps on two different pages!):
13. Observe the meanders, valley width, channel width, and vertical drop of each river and answer the following (be
sure to note the difference in scales!):
a. Which of the three rivers would you expect to have the steepest gradient and WHY?
b. Which river do you think is doing the least vertical erosion and WHY?
14. You have learned about features on a floodplain that indicate former positions of a river. For each map, list the
features you see that indicate a former position of a river, or note that none are present on that map:
a. Fig.10.9 (a), St.Francis River:
b. Fig.10.9 (b), Meadow River:
15. Examine the sediment transport bottles. Each bottle has the following sediment sizes: pebbles, coarse sand, fine
sand, silt/clay (combined for these purposes).
Shake the tube to suspend the sediments. Place the bottle on the table and record the order in which
the sediments settle out (p.141 will help you ID grain size):
First to settle _____________->_____________->_____________>___________ Last to settle
16. Recall from Part 1, Section A the relationship between energy of transport and grain size, and answer the
questions below:
a. When water is moving quickly, pebble (gravel) sand clay grains settle out (circle one)
b. When water then begins to slow down, pebble sand clay grains settle out (circle one)
c. When water is relatively calm, pebble sand clay grains settle out (circle one)
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17. Combining your knowledge of where sediments are found in relation to the energy of the transport agent (in
this case a river), and what is happening at each feature of a floodplain, Use Fig.10.8 on p.245 to help describe
where you think each sediment size would settle out. Use the sediment sizes you described in the sediment
transport bottle experiment.
a. Floodplain:
b. Channel:
18. So what happens when a river eventually drains into the ocean? Watch at least the first 30sec of this video and
answer the following questions:
https://www.youtube.com/watch?v=qyVbJukc-Vs
a. What is the name of the feature that forms when sediment piles up at the mouth of a river?
b. When a river meets the ocean what happens to the velocity of the water?
c. Briefly explain how this feature forms:
Section C: Observing Rivers in Google Earth
Adapted from “Observing Streams and Rivers in Google Earth” by Dr. Jennifer L. Piatek, Dept. of Physics and Earth Sciences, Central Connecticut State
University
Instructions for Using Google Earth
 Download the file placemarks_earth_rivers.kmz from OAKS but don’t open it.
 Open Google Earth
 Go to File-Open and navigate to the folder where you downloaded the kmz file
 Open the File
 Select “Stay on Earth” when the pop-up opens and asks if you want to go to Mars
 Under “Places” check the box next to “121 Homework earth” and click the arrow to open the folder
 Double click on the pins to navigate to each location
19. Locate Oxbow Bend (part of the Snake River in Grand Teton National Park, Wyoming). What will eventually
happen to Oxbow Bend?
20. Is there any evidence of this process happening in in the past along this portion of the river? If so, what is the
evidence?
Instructions for Using Google Earth to look at Mars
 Download the file placemarks_mars_fluvial_features.kmz from OAKS but don’t open it.
 Open Google Earth
 Go to File-Open and navigate to the folder where you downloaded the kmz file
 Open the File
 Select “Switch to Mars” when the pop-up opens and asks if you want to go to Mars. Or you can click on the icon
on the location toolbar that looks like Saturn to open a menu of locations and choose Mars
 Under “Places” check the box next to “121 Homework Mars” and click the arrow to open the folder
 Double click on the pins to navigate to each location
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21. Locate the “Feature in Eberswalde”, and zoom to an “eye alt” of 11 miles / 18 km with the place mark in the
center of the window (this location is a candidate landing site for the Mars Science Laboratory Mission):
a. Draw a simple sketch of this feature below:
b. How do you think this feature formed, and does it remind you of any features we see on Earth?
SKETCH:
Section D: Case Studies
Use the following website to answer the questions below: http://projects.propublica.org/louisiana/
22. Click on Explore the Coast and notice the information on the right hand side bar. Scroll down to the heading
“Speck by Speck, land built over centuries” and answer the following:
a. How did the Mississippi River Delta form?
23. Scroll down to the heading “Engineering the River” and answer the following:
a. What happened during the great flood of 1927 (damage, fatalities, etc.)?
b. What did the Army Corps of Engineers build after that flood?
c. What was the result of those structures?
24. Scroll down to the next section, “Effects of canals ripple across the wetlands” and answer the following:
a. Why did the oil companies dig canals?
b. What is a low estimate for the total number of miles dredged to build the canals?
c. What happened as a result of those canals in places like Lafitte?
25. Scroll down to the section titled “Consequences now clear” and answer the following:
a. Some basins around New Orleans are now sinking how quickly?
b. NOAA scientist Tim Osborn predicts SE Louisiana will see at least how much sea level rise by 2100?
Use the following website to answer the questions below:
http://environment.nationalgeographic.com/environment/freshwater/change-the-course/colorado-river-map/
26. The CO River supplies water for how many people?
27. What are the challenges facing the river?
28. Click on “Diversions” and answer the following:
a. What percentage of the CO River is used for agriculture?
b. What is the remainder used for?
29. Click on “Dams, Reservoirs, Canals, and Pipelines” and answer the following:
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a. How many dams have been built?
b. What is their purpose?
c. What two factors have put stress on the reservoirs?
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